Populations and Home Range Relationships of the Box Turtle

1
Populations and Home Range Relationships of the
Box Turtle

• Emily Marquardt
• February 15, 2007

2
Box Turtle Life History

• Live in mixed habitat
• woods (thick leaf litter), open fields, streams
• Omnivorous (mushrooms, berries, snails)
• Long-lived (human lifespan)
• Active April to October

3

• American
• Naturalist
• 1886

4
Lucille Stickels 1950 paper Populations and
Home Range Relationships of the Box Turtle

• Goals
• 1) To understand the home range relationships
• 2) To determine the size of the population

5
Home Range

• Definition
• An area over which an animal normally travels in
  the course of its daily activities

E. T. Go Home
6
Methods

• Cagle (1939)
• notching technique (mark-recapture)

7
Methods

• Breder (1929)
• Trailing Device with spindle of thread to track
  turtles

8
Ranges of 15 turtles occupying parts of a 5 acre
plot. Top males, Bottom females.
Travels of adult male during 8 days in 1945.
9
Methods

• Population Size estimated 2 ways
• By collections in one season
• Census trips, standardized for time and procedure

10
Results

• 2109 turtle collections in 3 years
• Adults occupy specific home ranges
• average male 330 ft, female 370 feet
• Some turtles have 2 home ranges
• Population size 4.6 turtles/acre

11
(No Transcript)
12
Box Turtle Population Research1950 to present

• Long term studies
• Genetics
• Herbivory
• Conservation

13
Population Tracking Techniques

• Mark-Recapture
• filing notches on marginal scutes
• Trailing devices
• Radio tagging
• GPS
• X-ray (eggs)

14
Long Term StudiesWildlife Research Center, MD

• Changes in Population (Stickel 1978)
• pronounced decline in population size
• -1965 to 1975 reduced by half
• Home Range Behavior (Stickel 1989)
• -size of home range did not differ significantly
  over 40 years
• Fifty year trends in Population (Hall 1999)
• - greater than 75 decline in population
• -found individuals greater than 70 years old

15
Genetics

• Promotion of Gene Flow by Transients
• Kiester et al. (1981)
• Transient turtle that moves through the
  environment without recrossing areas passed
  previously
• Study documents true transients.
• - suggests their importance in maintaining
  genetic similarity between populations and in
  aiding spread of advantageous genes

16
Genetic Effects of Persistent Bottleneck

• Kuo Janzen (2004)
• Loss of genetic diversity due to decrease in
  population size
• Bottleneck effects are different for long-lived
  vs. short-lived species

17
Kuo Janzen 2004 cont.

• Used microsatellite markers asses genetic
  diversity of small disturbed vs. large
  undisturbed population
• Computer simulations
• effective population size for small pop. (to
  maintain 90 alleles) is
• 300 over 200 yrs
• Long-live species could mask accelerated rate of
  genetic drift!

18
Herbivory

• Seed Dispersal by Florida Box Turtle
• Liu et al. (2004)
• What plant species are dispersed?
• Does passage through turtle affect germination
  rate and percentage?
• Current Study by Chris Swarth
• Measuring stable isotopes of C and N in toenails
  and comparing to wetland food items to determine
  habitats

19
Conservation

• Box Turtle Population Decline
• Habitat Loss and Fragmentation
• Pets
• Road Kill

20
Conservation

• Natural History of Box Turtle in Urbanized
  Landscape
• Budischak et al. (2006)
• Turtles persist and grow more quickly in
  urbanized areas, but suffer higher mortality
  rates compared to forested landscapes

21
Estimating the Effects of Road Mortality on
Turtle Populations

• Gibbs and Shriver 2002
• Modeling study
• integrated road maps traffic-volume data with
  movements of
• 1)small-bodied pond turtles
• 2) large-bodied pond turtles
• 3) terrestrial semi-terrestrial land turtles
• Roads networks of Eastern and Central US will
  limit (3) and (2) but not (1).

22
Translocated Box TurtlesCook (2004)

• Site abandoned airport in NY, 500 ha
• 335 turtles from Long Island
• Dispersal, home range establishment, initial
  survival monitored (radio tracked)
• Half developed home ranges
• 28 died and 24 left site
• Translocation potentially valuable but long term
  viability is uncertain

23
THEEND